The present invention relates to an ink liquid supply system in an ink jet system printer and, more particularly, to an ink liquid supply system for stabilizing the constant flow ink liquid supply.
A constant flow rate ink liquid supply system is highly required in an ink jet system printer of the charge amplitude controlling type to ensure accurate printing. To achieve the constant flow rate supply, it has been proposed to employ a constant flow rate pump. A typical construction of the constant flow rate pump and the related ink liquid supply system is disclosed in copending application U.S. Ser. No. 097,389, now U.S. Pat. No. 4,263,602 CONSTANT FLOW RATE LIQUID SUPPLY PUMP, filed on Nov. 26, 1979 by Masafumi Matsumoto and Matahira Kotani, and assigned to the same assignee as the present application. The corresponding German case was published on June 4, 1980 (DOS 2,948,131).
In such a constant flow rate ink liquid supply system, a pressure accumulator is provided for eliminating a pressure pulsation or a ripple created by the constant flow rate pump. The flow rate stabilization is not properly conducted in the above-mentioned constant flow rate ink liquid supply system when the ambience temperature greatly changes. Further, the above-mentioned constant flow rate ink liquid supply system requires a considerably long period to reach the constant flow rate operation after the system operation is initiated. A great variation in the temperature affects the size of the printed character in an ink jet system printer employing the above-mentioned constant flow rate ink liquid supply system. More specifically, when the printing operation is started at a considerably low temperature and the ambience temperature becomes high while the printing operation is conducted, the character size becomes gradually larger. This is not desirable in an ink jet system printer.
Accordingly, an object of the present invention is to provide a constant flow rate ink liquid supply system which ensures the constant flow rate ink liquid supply even when the ambience temperature greatly changes.
Another object of the present invention is to provide a constant flow rate ink liquid supply system which reaches a normal constant flow rate supply condition in a short period after initiation of the system operation.
Still another object of the present invention is to provide a constant flow rate ink liquid supply system, wherein the ink liquid pressure is varied in response to the variation in ambience temperature.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, the pressure applied to a pressure accumulator is varied depending on the variation of the ambience temperature. In a preferred form, a bimetal temperature detection element (pressure adjusting depressing member) is located above a pressure applying (depression) rod of a pressure accumulator for varying the pressure applied to the ink within the pressure accumulator in a fashion continuously depending on the ambience temperature.